Means for draining the low pressure blading of steam turbines



K. F REY ET AL MEANS FOR-DRAINING THE LOW PRESSURE BLADING OF STEAM TURBINES Dec. 1 1931.

- Filed Jan. 11, 1928 pm EIVTaQ 'Patentecl Dec. 1, 1931 blade dia I if at all affected leads to KARL FREY, or ENNETZBADEN, AND ADOLF MEYER, or xusivncnr, NEAR zumcrr,

SWITZERLAND, nssrenons r0 BAIDEN', SWITZERLAND MEANS non DRAINING THE LOW rrm'ssunr. 3mm or smart rungamns Application filed January 11, 1928, Serial No. 246,044, and in Switzerland. January 11, 1927.

The fact that in low-pressure blading it is the inlet edges of the moving blades which are principally if not exclusively damaged by water, whereas the fixed blades are hardly the greater part of the water, if not the whole, is thrown ofi from the moving blades and flows back thence into the fixed blading. This suggests the possibility of collecting and conducting away the water thrown off from the low-pressure blades of steam turbines in such a manner that it cannot flow back into the blading. This is comparatively easy of accomplishment in the lower part of the turbine owing to the inclination of the casing 1, as shown in Figure 1 of the drawings, necessitated by the increase of eter in the direction of flow 2 corresponding to the expansion of the steam.

Of the drawings Figure 1 shows in section the lower partof a turbine casing with fixed and movable blades; 7

Figure 2 shows a section of the upper half of a turbine similar to Figure 1;

Figures 3 and 4 show in section the upper half of a turbine incorporating the draining channels and passages formed according to the present invention.

A natural fall is provided in Figure 1, by the aid of which the water flows in the aforesaid direction and may be conducted away by suitable channels 3.

The conditions are otherwise in the upper part of the casing as shown in Figure 2, where the weight of the water partly or wholly counteracts the suction effect in the annular channels, in which a low pressure is main tained, and the water thrown off meetsthe inversely inclined wall 1 along which it flows and returns to the blading at 4 where it retards the motion of the blades and also causes erosion.

The object of the present invention is to conduct away and thus render harmless the water of condensation in the upper part of the casing. This is accomplished as shown in Figure 3 by arranging annular collecting channels 7 inthe planes of the inlet and outlet edges 5 of the moving blades 6 (or in at the conclusion that least one of said planes). The shape ofthese channels is such that the water thrown oft from the blades enters the radial annular openings 8 by virtue of its kinetic energy and is guided by the curved wall 9 into an annular collecting channel 10 where it is prevented from flowing outwardly and, in the top part of the casing upwardly extending lip 11. I

The annular collecting channels 10 may be made sufliciently large to carry off all the water collected. Alternatively they may be connected by means of auxiliary passages 12 with a further drainage channel 13 which conducts the water to the lower part of the casing. The passages 12 are preferably arranged with a natural fall towards the outlet in order to assist the suction effect by gravity. ure 4 if the section depicted therein be considered to be close to the horizontal lower surface of the upper half of the casing 1.

The water is finally conducted in the customary manner to a source of low pressure, such as the condenser for example.

The channels for collecting and draining off the water are preferably arranged in the roots of the fixed blading as shown in the figures. It will be understood, however, that they may also be located in the casing itself if the construction admits of this.

Having now described our invention, what we claim as new and desire to secure by Letters Patent is 1. In a steam turbine casing containing fixed and movable low pressure blading, means for draining the upper half of the low pressure blading including a plurality of ducts leading into an annular channel, the wall along which the condensed water travels in each duct being formed with a continuous curvature which merges into the wall of the said annular channel in order to utilize to the fullest possible extent the kinetic energy of the thrown off water of condensation.

2. Means as claimed in claim 1 wherein a plurality of said annular channels are provided with further ducts connecting the said channels with a common annular drainage channel.

back into the blading 6 by the,

This feature is illustrated in Fig- D STATES PATENT- ouricEjv AKTIENGESELLSCHAFT BROWN; BOVERI 8t CIE; '0]? LI.

3. Means as claimed in claim 1 wherein a plurality of said annular channels are provided with further ducts connecting the said channels With a common annular drainage channel, the said further ducts being arranged With a natural fall in the direction of flow of the condensed steam so far as is construetionally possible.

In testimony whereof We have names to this specification.

KARL FREY. ADOLF MEYER.

signed our 

